Carburetor



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CARBURETOR File@ sept. l26, 1952 s-sheets-.sheer 1 Sept. 25, 1934.

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P. w.` ENslGN CARBURETOR Filed Sept. 26, 1932 5 Shee'cs-Sheecl 2 ...MMI uw zlw 2` A5 /J e AJ 2 m iwl n w L 2 n 2 W. W

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CARBURETo-R Filed Sept. 26, 1932 5 Sheets-Sheet 3 EcorvoMxzEE PORT /055 nu VALVEN.

MAIN F'UEL.

NOZZLE PASSAGE.

Sept. 25, 1934. /i w. ENSIGN CARBURETOR Filed sept. 25', 1932 5 sheets-sheet 4 P. W. ENSIGN Sept., 25, 1934.

CARBURETOR 5 Sheets-Sheet 5 Filed Sept. 26, 1932 Patented sept. 25, 1934 UNITED STATES 1,974,450 CARBURETOR Paul W.` Ensign, San Marino, Calif., assignor to Ensign Carburetor Co. Ltd., Huntington Park,

Calif., a corporation of California Application September 26, 1932,Serial No. 634,838

Claims. (Cl. 261-72) 10 is an improvement and development of the type of air valve carburetor which` is the subject matter of theprior applications of Roy F. Ensign and Paul W. Ensign, entitled Carburetor and fuel` converter, Ser. No. 581,816, filed Dec. 18, 1931 which has matured into. \Patent No. 1,948,702, dated Feb. 27, 1934, and of Paul W. Ensign, entitled Carburetor, Ser. No. 498,040, filed Nov. 15, 1'930, which has matured into Patent No. 1,912,573 dated' June 6,' 1933 as the present carburetor utilizes the general structure and action ofthe carburetor of these prior applications. To'tho'se structures and actions, however, the present in- 'vention adds certain modifying features that makefor better al1-range efficiency and control, and render the Icarburetor capable of universal application to different engines. The invention further provides a new arrangement and interrelation of idling and accelerating systems, and other improved features designed and operating 30 to increase eiciency and maintain high emciency throughout all ranges.

An illustrative specificv description of preferred embodiments will best serve to make the invention itself understood. For the purpose of such description, reference is made to the accompanying drawings showing the illustrative embodiment, and in which:

Figure 1 is a diagrammatic section showing the principal parts of the carburetor, several of the parts asl shown in this 'view being rearranged in position to clarify the description.

Fig. 2 is a plan of the carburetor as actually constructed in its preferred form;

- Fig. l3 is a fragmentary sidey elevation) taken in the aspect indicated by line 3 3 of Fig. 2, parts of the connection between the choke shaft and throttle being shownin section;

Fig. 4 is a fragmentary longitudinal section taken as indicated by line 4 4 in Fig. 2, with parts in elevation in the same aspect;

Fig. 5 is an enlarged lvertical section of the throttle-stop mechanism shown partly in elevation in Fig. 4;

Fig. 6 is a side elevation taken in the aspect .55 indicated by line 6 6 of Fig. 2;

The particular objects of the,

Fig. 7 is a central vertical section in the same aspect as that of Figs. 1 and 6; see also the line 7 7 of Fig. 8;

Figs. 8 and 9 are transverse vertical sections on lines 8 8 and 9 9, respectively, of Fig. 7.

Figs. 10 to 12 are fragmentary vertical sections on lines 10 10, 11 11, 12-12, respectively of Figs. 8and 9; see also lines 10 10, 11 11, 12 12 in Fig. 13; v y

Fig. 13 is a fragmentary horizontal section on 65 line 13 13 of Fig. 7;

Fig. 14 is a vertical cross section on line 14-14 of Fig. 2; v

Fig. 15 is a horizontal section on line 15 15 of Fig. 9;

Fig. 16 is an enlarged fragmentary View showing `the valve V and associated parts in perspective, the valve being in idling position;

Fig. 17 is a fragmentary enlarged view of the valve V the sectional aspect and position of 75` Fig. 1. l

The drawings show in full scale my preferred' carburetor design, and throughout, the parts are shown approximately in their actual sizes for an inch and one quarter sized carburetor. In the diagram of Fig. 1 the control valve V is relatively enlargedfor clarity of illustration. In describing certain partsports, orifices, etc., where sizes are important, the present adopted sizes are given hereinafter so that the specific structure and operation of this illustrative embodiment may be fully understood.

The carburetor embodies two main body castings A and B, the first containing the air passage C, the second containing fuel chamber D, and the two meeting on the faces F and secured together by screws 10. The body part A with its air passage and appurtenant parts will first be explained.

Air passage C having its intake at 11, com` 95 prises a venturi 12, andan outlet at 13 controlled by throttle 14 on the shaft 15. At the, throat of the Venturi are ports 16 leading through the Venturi wall to an annular chamber 17 from 1 whence is derived the air velocity depression which is used (modified as afterwards described) for initial lifting and. metering of the fuel. The venturi flares outwardly at 12a above its throat, and above the outwardly flaring portion, the wall 105 of the air passage curves reversely at 19 to bring the flare back to the diameter of the air outlet.

In the venturi at the are is contained a vertically movable loating air valve 20, the valve being mounted on vertical guide stem 21 which 110 sol from the dash pot casting 23.

"The valve 20 has a diameter such as to substantially fit the Venturi throat (see Fig. 7) and, when the valve is lifted to its uppermost position, to allow an annular air passage at P through the flare around the valve. This annular air passage, when wide open (see Fig. 1) has a crosssectional area somewhat less than the effective area through the Venturi throat. The contours of the venturi,` the are and the valve are substantially those described in the vsecond mentioned application before referred to, as, in fact, are also the general air passage .and air valve arrangement now being described. Associated with the valve is the fuel filled dash pot 25 containing a valved piston 26, mounted on the lower end of valve stem 21. The floating disc 26a of this piston has two holes 2Gb of about ff@ inch diameter, in the size of carburetor being described; and the valve with its connected moving parts weighs about 31/2 ounces. The piston disc fits the dash pot cylinder rather loosely, so that on upward valve movement, the liquid will leak past the disc; but the clearance around the disc will be suniciently restricted to the point that upward movement of the 'valve is considerably retarded. On downward movement, the valve drops more quickly by reason of the liquid being allowed to pass through openings 2Gb, but the valve is not permitted to drop freely.

The valveA carries a dependent flanged sleeve 29 which extends around the valve stem and bearing 22 to protect the stem and afford means for engagement of a choke arm 30. This arm is mounted on choke shaft 31 (see Fig. 4) to have a limited rotative play thereon by yvirtue of pin 32 and slot 33, a spring 34 urging arm 30 in the direction indicated by the arrow with reference tothe shaft. When the shaft is rotated in that direction to bring arm 30 down on ange 29a, (see the arm 35 and operating wire 36 in Fig. 6) the arm presses and holds the air valve down, either positively, when shaft 31 is rotated far enough to take up the slack motion between the shaft and arm, or yieldingly as when the shaft is backed off far enough to allow spring 34 to come into play. Thus, on starting a cold motor, the choke shaft is rotated to the limit to hold the air valve positively closed for a short time, and then the shaft is backed off a little and the air valve is held down by the comparatively light pressure of spring 34, thus applying to the air valve a mild choking action while the engine is warming up.

In order to insure a slight throttle opening Whenever. .the choke is ,in operation, a push rod 38 (see Fig. 3) has its lower end resting on a flat 39 on' choke shaft 31, ,so that rotation oi the shaft to choking position will raise the rod. The upper end of this rod extends througha guide opening in the body lug 46 and stands under an arm 40 mounted on throttle shaft 15. Upon yrotation of the choke shaft, the rod acts to push the arm 40 up slightly and to open the throttle to such an idling position as to give the engine alittle more volume of mixture than is necessary when the engine is idling after becoming hot.

Engaging the same throttle arm 40 is the adjustable throttle stop device shown in Figs. 4 and 5. The body oi the stop is formed by the nipple 45 screw-threaded into lug 46 in the carburetor body, spring 47 acting as a lock to prevent the stop from turning accidentally. The

l 1,974,450 slides in guide bearing sleeve 22 extending up` lower end of nipple 45 is shaped to form a small cylinder 48 in which a valved piston plays in oil. The valved piston, mounted on the lower end of rod 49, is made upof a disc 50 loosely surrounding a reduced rod portion 51 and adapted tc seat upwardly against rod shoulder 52, the piston disc fitting the cylinder with a small leakage clearance. At the lower end of rod 49 a recessedfwasher 53 forms an upward seat for the top of spring 54 confined by plug 55 that closes the lower end of the cylinder. The lower surface of piston disc 5G is grooved as at 50a to prevent the disc from making a sealing contact with washer 53 when it seats on it, and the bore of the disc is grooved at 50h to pass fluid during upward movement of the rod.

Adjustment of nipple 45 xes the final position of the throttle when closed to the minimum desirable opening for engine idling. As the throttle closes, its arm 40 comes first into contact with rod 49 which, due to the action of spring 54, stands at open throttle above the position shown in Fig. 5. This spring normally holds the rod up to such position'that rod shoulder 49a engages the upper end of the cylinder. In the design here illustrated, the throttle arm engages rod 49 when the throttle is about 12 open, and from that point on the throttle closing movement is retarded by the dash pot action of the piston disc. Leakage of oil past the piston is at such rate that iinal throttle closing, instead of being substantially instantaneous as usual, is retarded sufficiently to allow the air, which still passes in appreciable I quantity through the manifold, to pick up any t excess fuel remaining from an immediately previous heavy load condition, and to pass that fuel into the engine before the throttle closes to such a point that the then smallI amount of air would not be able to form a combustible 4mixture with the excess fuel. SA frequent cause of engine killing is thus removed.

It will be understood that thethrottle is closed by any suitable means; the usual throttle closing spring is here pre-supposed but not illustrated. Dash pot spring 54 is relatively light and 120 strong enough tc raise the piston and rod, -but is overcome and compressed by the stronger throttle closing spring.

As in the carburetors of the mentioned application, the general function of air valve 20, play- 'ing in the venturi and theflare, is to impose on the air stream a predetermined resistance which, at all throttle positions and corresponding posi` tions of the air .valve in equilibrium, places upon the air stream ,in space S between the two valves, a depression greater than that at the Venturi throat. Under all operating conditions, the air valve 20 will be raised from its seat on the Venturi throat, although at idlingthe clearance between the valve and the surrounding passage wall will,be comparatively slight. Thedeprssion at the Venturi throat, except at idling, varies sub. stantially directly with the volume, and velocity, of air passing through the carburetor. The depression in space S between the valves will be determined by such factors as the speed of engine operation and throttle position and also the position oi. the air valve 20.

During changing conditions of engine opera.- tion,`the respective depressions in the space S 45 and at the Venturi throat vary, as does the relative depression at these points. As the flow of air through the carburetor increases from around idling operation to about one quarter open throttle position, the depression applied to the fuel 15C? riser through passage 82, which parts are hereinafter described, decreases in proportion to the rate of increase of air flow, due to the fact that the depression between the valves in space S is substantially constant..l From that point on to full open throttleposition, the increase of fuel metering depression isl slightly greater than the rate of increase in flow of air, since at this time the air valve has reached its upper limit of travel and the area at P remains constant while the rate of air now continues to increase.,

The two varying, but mutually interrelated, depressions between the valves and at the Venturi throat are used, as in the carburetorsfof the applications mentioned hereinabove, for measuring, feeding and delivering the fuel during normal running; depression from above the throttle likewise influencing the fuel lifting depression at or near idling. However, in accordance with the present invention, the actions of these depressions are modified and are interrelated with other actions as will hereinafter appear. y

Referring now more specifically td Figs. 1, 7 and 14, it will be seen that the body casting B contains, among other things, a fuel chamber D in which the fuel level is controlled by valve 60 operated by float 61. The float is`pivotally carried on a bracket 62 depending from the fuel chamber cover 63, anda sloping apron 64 under the valve serves to catch at least some of the fuel delivery and guide it to the open upper end of passage 65. This passage, leads first downwardly and then (see Figs. 8 and 10), laterally to the faceF where the two body castings meet, tliel passage then being prolonged in casting A by the passage 65a (see Figs. 1, 9, 10) to the dash pot 25. The latter is thus kept full of liquid when the carburetor is operating, but without any liability of continued drawing of fuel when standing, in.

\ the liquid level L therein to a high point, in order that the height to which fuehbeing fed from the supply chamberis required to be lifted in being taken into the discharge or nozzle passages, will bereduced to a small distance. Because of the high positioning of the fuel chamber, the upper end of the air valve guide sleeve 22 is allowed to terminate at a point below the fuel level L in the supply chamber. Since however, dash pot 25 communicates with the supply chamber only by way of passage 65 whichterminates above the fuel level, it will be seen that upon standing, no lappreciable fuel leakage can occur upwardly between valve stem 21 and the guide 22, since only a negligible quantity of fuel will remain standing in passage 65 at a level above the upper end of sleeve 22.

In order to preclude the possibility of a capillary seal in the form of fuel between valve rod 21 and the guide 22, being established to inhibit proper functioning of the dash pot, I provide an orice 201 extending through the valve 20 and leading into the space at the upper end of the guide sleeve. Suflicient suction will be applied by way of this orifice to the space 202 to prevent the formation of the capillary seal, although the depression so communicated will be slight-and insufficient to cause any appreciable amount of fuel to overflow the guide sleeve.

-From the air intake, a balance passage indi- 'v cated at 70 in Fig. 1 leads at 70a through the wall of casting A to face F and is thence extended as a groove of approximate inverted U-shape, in the i communicate with the fuel chamber D through a face of the casting. In Figs. 9 and 10 which show the actual structure, the up leg of this inverted U is designated at 70h, the horizontal run 70e, and the down leg 70d. The reason for the peculiar shape of the passage is to prevent fuel flowing from the bowl While standing, and to afford easy and short connection with other passages, as will presently appear. In diagrammatic Fig. 1, the inner end of the balance passage 70 is shown to 85 loose nap valve 71, below the liquid level. In ac- -tual structure, this final communication with the fuel chamber, as shown in Fig. 11,'is via an nclined short passage 70e that connects with the lower end of groove leg 70d and passes from face F through the wall of casting B directly to the chamber.

Leading from the main air passageat a point between the air valve and throttle, where it is subjected to the depression existing in space S between the valves, is a passage designated as a whole in Fig. 1 by the numeral 72, this passage communicating with the fuel chamber above the liquid level', In the actual carburetor this passage is formed of two short drill holes in the two castings. Drill hole 72a Y(see Figs. 9 and 10) extends directly from the main air passage to face F, and registers with drill hole 72b (see Fig. 10) which extends from face F diagonally down into the upper part of chamber D.

In operation, fuel occupies the fuel chamber to a constant level as shown at L, Fig. 1, and tends to rise to the same level in balance passage 70. The depression constantly imposed on the fuel chamber via passage 72, causes the liquid level in balance passage 70 to bel depressed to such a point that air from the balance passage can ow under the edge '73 in suiicientquantity to relieve the depression vabove the fuel in the chamber.v The pressurek (hydrostatic) of theliquid being then substantially fixed at the point 73, and that point being very nearly under the column up which the fuel is liftedv out of the fuel chamber,

- the lift is thus substantially not affected by tipping of the carburetor. This feature of structure and operation is the subject matter of prior Patent No. 1,805,763, R. F. Ensign, May 19, 1931, where the operation is fully explained.

The main fuel riser, located near point 73, is shown here as comprising a tube 74 having its 125 `lower end in communication viakpassage 75 withl ing up .against plug 78 to prevent accidental maladjustment.`

A passage 82 leads off laterally from riser bore 79 above orifice' 76, and is formed in a tube 83 open at its end toward the riser bore but closed at its other end4 which projects into valve bore 84. The actual construction is shown in Figs. 7 and 8. In Fig. 1 the passage 82 is necessarily shown prolonged to the left from tube 83 in order to reach riser bore 79 as there shown. Near its closed end, 145 tube -83 has a radial orifice 85 on a horizontal axis, and directly opposite this orice is a short orifice 86 `'leading to face F through the wall of thevalve bore, see Figs. 7 and 13.` It will be noted that riser bore 79 and valve bore 84 are 150 located closely behindface F, as are also the various other passages and appurtenances to be described; so that all passages reaching face F are very short.

Orifice 86 at face F registers directly withmaln fuel nozzle 87 which projects through the wall of the main air passage and through the wall of the venturi 12 into the main air passage ,at its point of greatest diameter at the flare.

The rotary or oscillating control valve V occupying the valve bore 84, is perhaps best shown in Fig. 16, together with the immediately connecting passages. Passage tube 83 projects into the bored end of valve V, that end of the valve having an angled cut-off lug 90, which, in the position of the valve shown in Figs. 7 and 16 (idling position) cuts off the opening 86 about one-half. In the wide open position ofthe valve, see Fig. 1, this angled cut-off lug moves off opening 85 (direction of rotation toward open position being shown by the arrow in Fig. 16', which direction is counterclockwise in Figs. 1 and 7) so that the opening 86 is then wide open. Valve V is so connected with the throttle that opening movement of the throttle is accompanied by opening movement of valve V, and vice versa. A suitable connection between thevalve and throttle for this purpose is shown to comprise a connecting link 91 (see Fig. 6) that connects between arm 92 on the. throttle shaft and arm 93 on the valve V. One.

end of link 91 extends through an opening in lug 92a carried on the throttle shaft arm, there being a coil spring 98 confined between lug 92a and an annular shoulder on the link. A nut 99 isl threaded on the outer end of link 91, washer 99a being placed between the nut and the throttle arm lug. By virtue of the described connection4 between the throttle arm and link 91, the relative positions of the latter may be adjusted as desired to` bring about proper coordination inthe operation of the throttle and valve V. A at spring 94 mounted on a stud 95 presses against the valve end to hold it longitudinally in place within bore 84.

Entering the valve bore obliquely from beneath is an air passage 100 that leads from face F where itregisters with a short passage 100e (see Fig. 17) that communicates with space 17 around the Venturi throat. The function of passage 100, as will later be seen, is to communicate the depression at the Venturi throat to the main fuel passage. lIt will be noted that passage 100 remains fully open' to the valve bore 84 at all positions of the valve, and that it is only port 86 that is affected by valve movement.

In Figs. 1, 16 and 10, a short passage 105a is seen leading from face F, where it communicates with leg 70h of the balancing passage, into the valve bore 84. `In actual structure, this passage a is horizontal and is registered by a horizontal part of valve passage 10517. To eliminate complications in diagrammatic Fig. 1, the passage 105a is there shown entering the valve bore Vertically from beneath and the valve passage 105b is shown as straight. Operation is the same in both cases. The other end of valve passage 105b is registerable with vertical passage 105e controlled by adjustable needle 106; and a cross connecting'passage 105d connects the needle valve bore 105e with the main fuel riser bore 79. See Figs. 8, 10 and 11 where this cross connection is shown in structure. In diagrammatic Fig. 1, the cross connection is shown at 105d.

The function of this` valve controlled passage is, at certain intermediate throttle positions, to

restrictedly place the mainffuel .riser .in communication with air from the balance tube, (from the main air inlet) to controllably reduce-.the fuel raising depression in the fuel riser and thereby to economize in the use of fuel during the medium running ranges. The fuel riserpri.- marily gets its fuel raising depression fromf-the Venturi throat through the passage 100 as prefviously described. Substantially the depression at the Venturi throat isproportionate. to :the amount of air passing through it, andconsequently, uncontrolled by valve V, the amount o ffuel lifted in riser 79 and flowing through passage 82 would be also substantially proportionate to the amount of air. This fuel, it may be here noted, does not vpass on from the valve through passage 100 to the Venturi throat, but is pulled out of the .valve bore 84 through passage 86 and-main fuel nozzle 87, by the greater depression present at the fuel nozzle due to the action of air valve 20 which has been explained.

'I'he depression at the fuel nozzle therefore increases the depression applied to the fuel riser so that the resultant depression is one .made up of the air proportionate depression fromthe Ven- 100 turi throat, and an additional depression created by the air valve. This latter depression does not vary with the air volume, but varies in accordance with throttle position and operating conditions, as previously stated. The total or resultant fuel lifting depression, uncontrolled by valveV, would not be in proportion to the air volume. but would be too great at low ranges and progressively less as the higher ranges f are reached.

It is desired, in the final composite action of the carburetor, to lift `proportionatelymore fuel at low ranges around or j ust past idling, less proportionate fuel during medium ruiming ranges, and again more proportionate fuel (proportionsns for perfect mixture) at full operation. To accomplish this final result,`the valve V so controls the-fuel lifting depression that, assuming adjustment at needle valve 77 to be such as to give perfect mixture with the throttle and valve V wide open, the mixture at and near idling would vbe preferably somewhat rich, and themixture through medium ranges somewhat lean. The valve accomplishes this control by the action of lug 90 in restricting passage 86 in the closing movement of the valve, and by the effect of the valve economizer ports, as I shall presently explain. f

It will be seen that as the valve V moves from the positions of Figs, 1 and 17, corresponding to open throttle position, to the position of Fig. 7, at which the throttle is moved to closed or idling position, lug 90 closes passage 86 down to about one-half, and in so doing progressively reduces the fuel lifting depression applied to the fuel 135 riser from the nozzle 87. The result of depression control solely by valve V is that the correct or desired proportionate amount of fuel is lifted at low speeds (just above idling) and also at full operation; but that somewhat, though not a 1 great deal, more than is desired would be lifted at the medium ranges for greatest eciency and economy during medium operation, in the absence of the economizer.

It is then the general function of the econo- 145 mizer passages 105a, etc. to reduce the fuel lift at medium ranges to the desired economical (lean mixture) proportion; and this is done by controllably applying to the fuel riser 79, a bleed of air from balancing passage 70 during those .15@

medium ranges. The maximum bleed and relief of the fuel raising depression is controlled by adjusting needle 106, see Fig. 10. The graduated application of that relief is applied by valve V when its port 105D sweeps into and out of register with .the economizer passage 105a as the valve moves, in cooperation with the throttle,

' and registering with the economizer port 105a in the idling position of the valve as shown. The purpose of this restricted port 105) is not primarily to effect a reduction in the fuel lifting depression at idling, but rather to admit a small amount of air to the riser borel for the purpose of preventing passage 82 from clogging withfuel, or from gathering an excess fuel accumulation, during idling operation. As will be understood, the admission of a slight amount of air through 105]e will be suicient to sweep the main fuel passage clear of accumulated fuel.

Upon movement of the throttle to intermediate position and valve V to the point at which port 1051 is brought into register with port 105:1., a

bleed of air to the riser bore is established to' reduce the fuel liftingdepression to such an extent that during the intermediate ranges of operation, less proportionate (to the amount of air) fuel is supplied, and the final fuel and air mixture is reduced in fuel content to provide the leaner and more economical mixtures desired in the intermediate range of operation. Upon movement of the throttle to full open position, port 10511y is moved out 'of register with 105a and the comparatively higher fuel lifting depression is restored unrelieved to give a proportionately richer mixture at full operation. It will be noted that the mouth of port 10517 adjacent 105e is enlarged so as tosremain in communication with 105e at all positions of the valve.

The idling by-pass is shown in Fig. 17 to be made up of a passage 112 leading downwardly from an intermediate point in the nozzle 87 to the horizontal groove passage 11111, see Fig. 9, comprising a portion of passage 110. The .passage 110 enters the main air passage above the throttle (see Fig. 1) and includes the grooved passage llOal in face F of casting A, the latter including the generally U-shaped groove passage llla in face F. Restricted bore 113 is shown connecting 110a with' 111a at the upper right in Fig. 9. Returning' now to Fig. 17, passage 1111) is shown to communicate with the valve bore through bleeder port 115 and with the main air passage at a-point below nozzle 87 by way of bleeder port 116. In the diagram of Fig. 1` the idlingby-pass is shown more simply as passage 110, restricted-passage 113, and passages 111 and 112, with the interconnecting bleeder ports 115 and 116.

During idling operation, manifold depression applied to passage 110 above the throttle is restrictedly communicated through orifice 113 to passage lllb, this depression being modified at the nozzle by the air bleeds through ports 115 and 116. Under idling conditions, this depression so applied to passage -112 is of course greater, since the throttle is substantially closed and the rate of air iiow through the carburetor comparatively low, than the depression applied through passages 100 and the nozzle 87. Therefore, at idling the fuel is drawn through passage 86, which is partly closed by the valve lug 90, into the nozzle 87 and is thence drawn down through 112 into passage 11`1b to be finally taken, together with air taken in through bleeder ports 115 and 116, to passage 110 whence it is discharged into the main air passage.

Just as there are two effective depressions e tering into the metering of fuel during normal operation to the main fuel nozzle, that is, the Venturi throat depression which draws fuel into and from the main riser, and the greater depression at the nozzle which causes the fuel taken into the valve chamber by the first mentioned depression to be discharged through the nozzle, there are also two effective depressions which similarly act in the metering of fuel during idling operation. The rst of these depressions is that applied to the main nozzle 85 which causes fuel to be taken into the valve chamber and. thence through ports 112 and 115 to passage 111D. The second and greater depression is that communicated to lllb from above the throttle through passage 110. It may be mentioned that fuel will continue to be taken into passage 11111 and vdischarged through idling by-pass 110 so long as the depression above the throttle is sufiicient to draw fuel from the nozzle and valve chamber.

Port 115 is provided primarily' for the purpose of drawing into passage 111b any fuel during idling operation, thatnmay tend to flow down along the wall of the valve bore, or to drop from. valve port 85 instead of passing directly to the nozzle 87. Thus, idling fuel may pass into passage lllb by way of either or both of ports 112 and 115. l

The purpose of port 116, in its peculiar position relative to the venturi and valve 20, is essentially to iniiuence the operation of the economizer system, by preventing excessive thinning of the fuel and air mixture being supplied the engine when the valve Vis in position corresponding to normal intermediate operation, with valve passage 10517 in registration with ports 105a and 105e, but with the engine operating at a speed (say 10 miles per hour) well below normal intermediate speeds. This condition is encountered frequently when the throttleand therefore the valve V are in intermediate positions, but the engine is so loaded as to operate at a speed considerably below normal intermediate. In the absence of port 116, there would be a tendency, dueto the registration of the economizer passages, for the depression applied to the fuel in the reservoir to be so great as to reduce the richness of the combustible mixture below that required for operation under these conditions. Port 116 accordingly acts to offset the excessive economizer effect by increasing, by just the necessary amount, the effective fuel metering suction.

During normal intermediate running when the economizer is in operation, air valve 20 rises above port 116, and the latter at such time has no substantial effect on the fuel metering. When the speed and therefore the flow of air through the carburetor decreases, with the throttle and valve V remaining in intermediate position, the air valve falls below port 116. 'I he result is that an added suction, increasing the effective metering suction on the fuel riser, is communicated through port 116 and thence through 115 and to some extent through 112, to the valve chamber.

As stated, this added suction is, by proper regulation of the port size, made sufficient to oifset the tendency of the economizer system to produce an over-lean mixture.Y

I shall now describe the parts of the carburetor provided for accelerating operation. Under the fuel chamber there is a diaphragm chamber 120 closed at the bottom by diaphragm 121 pressed upwardly Y'by spring 122 resting in a cap 123 which forms a depression chamber 124 cornmunicating with the idling by-pass via passage 125, a passage that, as shown in Fig. 7, runs between chamber 124 and the lower horizontal extension 110b of the idling by-pass groove llOaY Passage 125 is air bled by restricted 'Y bore 12517 connecting with the air intake, merely*V (see Fig. 9).

for the purpose of introducing a little air at that point tocarry up the idling fuel andprevent itY Y11,01) directlyinto the main air intake (see Figs.

9 and 11). In essence it will VVbe seen that the connections of'rdepression chamber 124 are thus merely the main air passage above the throttle (Via passage 125 and the idling passage 110) and tothe air intake (via small passage 125D to the .intake or to the balance passage .l

Rising from diaphragm chamber 120 is a passage 127 (see Fig. 12 for its construction) that terminates in the upwardly directed nozzle 128. This nozzle has its upper end in the lateral fuel passage 129 that is open to the fuel chamber D. When the throttle is not open, depression applied through the idling by-pass draws the diaphragm down and fuel owsin to lill' chamber 120. If at any time the throttle is moved toward open position, the depresssion lessens, the diaphragm moves up, and fuel is expelled forcibly through nozzle 128. The Miet from this nozzle is projected directly at and restrictedlythrough the Venturi orifice 130, and the velocity action there entrains further fuel which is standing in passage 129.

The jet, passing on through the venturi 130 into the accelerating well 139, is projected against the body of vfuel standing in bore 139 above the venturi, and against the vertically movable orificed piston 131 in the bore. .As the fuel is suddenly jetted up throughthe venturi, the fuel irl` bore 139 above the piston is moved out through passage 134 in plug 135, and thence through the passage 136 to and'through the accelerating nozzle 137. Passage 136, is, in the construe 'on, made up of the short passage 136a (see Fig. 12) that registers, at face F, with .passage 1361) leading to nozzle 137. Piston 131 is more or less loosely fitted within bore 139 and Serves, Lafter discharge of the required amount of fuel standing above it for sudden acceleration, to restrict the continuance of the fuel discharge by coming into engagement with the lower end of plug 135 with its aperture 132 in register with the plug Y passage.

'lil

In the illustrative construction herebeing described, the orifice 132 in pistons 131 is a. No. 'I0 drill while the orice at 134 is preferably somewhatlarger, as is also the nozzle orifice at 128.

Nozzle 13,'1 has an orifice the size of a No. 53 drill. This nozzle is situated, like main nozzle 87, at

bled by the-rather large passage 138 (No. 40 drill) connecting with the balance pasasge as shown in Fig; 9, is just sufficient at all times to keepY fuel up in the accelerating well (the bore 139 in which piston 131 plays) to approximately or above the level of the lower end of plug 135. In normal operation, a small amount of fuel, (one or two per centl of the total being used) may be drawn more or less constantly into the main airpassage via the accelerating nozzle.

Fuel normally lls the accelerating well up to at least'the lower end of plug 135, so asto be instantly available for discharge through passage 136a to the nozzle when acceleration is required. Because of the-limitations in diagrammatic Fig. 1, the true position of the fuel level relative to the accelerating well does not appear, although in Fig. 12, the liquid level is shown at L at its actual height relative to the accelerating well parts. On opening of the throttle, the immediate upward movement of diaphragm 121 forces fuel above it through passage 127 and nozzle 128 and thence upwardly through the'venturi 130 and thus forces 95 a charge of fuel to the accelerating nozzle as previously explained. Further fuel-Y may oo ntinuerto be jetted through the piston orice until movement of the diaphragm under the inuence of the spring `is complete, or depression is apl0@ plied to the diaphragm to counterbalance the spring pressure. It will be Yunderstood that the higher depresssion placed on nozzle 137 when the throttle is opened, is due to the fact that instantaneous upward movement of the air valve is retarded by the action of the dash-pot at its lower end.

In order to complete the specific description ofthe illustrative actual structure, the sizes of certain of the passages, in addition to those pre- 110 viously described as to size, will be given: without, however, any limitation being implied in this or in any other specific description of actual structure, all of which is only to be taken as illustrative. Y

The main fuel inozzle 37 has a bore of size No. 22 drill; 'the orifice at 85 is a No. 30 drill, and needle controlled orifice 76 in the fuel riser is a f No. 22 drill. The idlingby-,pass bore at Y110 is a No. 30 drill, the restriction at 113 a No. 48 drill; 120 and orifices 115, 116 and 112 of Nos. 50, 43, 6G

drills, respectively. The needle controlled passage at e, the controlled economizer-passage, is a No. 30 drill, as is also the valve passage 105 b and orifice 105'a, bleeder passage 1051 being a No. 125 60 drill. The main suction passage 100 is a No. 16 drill, .the size of the Yopening at 100a, is 1% in diameter. The balance passage is made to have a cross sectional area approximately that ofa three-eighth inch drill.

I claim: Y. 'i

1. In a carburetor having amain air passage with a constriction therein, a. fuel chamber and a throttle valve in said passage; a depression chamber in fuel lcommunication with the fuel depression chamber and the constriction in the air passage to apply to the depression chamber the depression caused by air velocity at the constriction, a fuel nozzle communicating with the depression chamber and discharging into the main air passage, means in the air assage for establishing on the fuel nozzle a depression greater than that at said constriction, and valve means operatively connected to said throttle, for" regulating the depression applied to the depressionchamber from said nozzle.

2. In a carburetor having a main air passage with a constriction therein, a fuel chamber and .a throttle valve in said passaeera" depression 150 chamber in fuel communication with the fuel chamber, an air communication between the depression chamber and the constriction in the air passage to apply to the depression` chamber the depression caused by air velocity at the constriction, a fuel nozzle communicating with the depression chamber and discharging into the main air passage, an air valve floating on the air stream in the air passage for establishing on the fuel nozzle a depression greater than that at said constriction, and means comprising a valve operatively connected to said throttle, for regulating the depression applied to the depression chamber from said nozzle.

3. In a carburetor having a main air passage with a constriction therein, a fuel chamber and a throttle valve in said passage; a depression chambenin fuel communication with the fuel chamber, an air communication between the depression chamber and the constriction in the air passage to apply to the depression chamber the depression caused by air velocity at the constriction, a fuel-nozzle communicating with the de- A pression chamber and discharging into the main Y air passage, an air valve floating on the air stream in the air passage for establishing on the fuel nozzle a depression greater than that at said constriction, a valve in said depression l chamber connected to said throttle and operable to regulate the depression applied to the depression chamber from said nozzle.

4. In a carburetor having a main air passage With a constriction therein, a fuel chamber and a throttle Valve in said passage; a fuel riser passage in communication with the fuel cham-- ber, a depression chamber and a passage connecting the depression chamber with the riser passage, an air communication between the depression chamber and the constriction in the air passage to apply to -the depression chamberK the depression caused by air velocity at the constriction, a fuel nozzle communicating with the depression chamber and discharging into the main air passage, an air valve floating on the air stream in the air passage for establishing on the fuel nozzle a depression greater than that at said constriction, a Valve in said depression chamber connected to said throttle and operable to regulate the depression applied to the depression chamber from said nozzle.

5. In a carburetor having a main air passage with a constrictiontherein, a fuel chamber and a throttle valve in said passage; a fuel riser .i passage in communication with the fuel chamber, a depression chamber and a passage connecting the depression chamberwith the riser passage, an air communication between the depression chamber and the constriction in the air passage to apply to the depression chamber the depression caused by air velocity at the constriction, a fuel nozzle communicating with the depression chamber and discharging into the main air passage, means in the air passage for establishing on the fuel nozzle a depression greater -than that at said constriction, and a valve for controlling the flow of fuel from said riser passage to the depression chamber. l

6. In a carburetor having a. main air passage lwith a constriction therein, a fuel chamber and a throttle valve in said passage; a depression chamber in fuel communication with the fuel i chamber, an air communication between the depression chamber and the constriction in the air passage to apply to the depression chamber the depressioncaused by air Velocity at the constriction, a fuel nozzle communicating with the depression chamber and discharging into the main air passage, an air valve floating on the air stream in the air passage for establishing on the fuel nozzle a depression greater than that at said constri'ction,4 and -means for communicating a depression varying in accordance with throttle position, from said depression chamber to the fuel chamberabove the fuel level therein.

7. In a carburetor having a main air passage with a constriction therein, a fuel chamber and a throttle valve in said passage; a depression chamber in fuel communication with. the fuel chamber, an air communication between the depression chamber and the constriction in the air passage to apply to the depression chamber the depression caused by air velocity at the constriction, a fuel nozzle communicating with the depression chamber and discharging into the main air passage, an air valve floating on the air stream in the air passage for estabishing on the fuel nozzle a depression greater than that at saidconstriction, and means including a valve operatively connected to said throttle, for applying a variable depression to` said fuel chamber above the fuel level therein.

8. In a carburetor having a main air passage with a constriction therein, a fuel chamber and a throttlevalve in said passage; a depression chamber in fuel communication with the fuel chamber, an air communication between the depression chamber and the constriction in the air passage to apply to the depression chamber the depression caused by air velocity at the constriction, a fuel nozzle communicating with the depression chamber and discharging into the main air passage, an air valve floating on the air stream in the air passage for establishing on the fuel nozzle a depression greater than that at said constriction, a passage for communicating de-` pression from said depression chamber to said fuel chamber above the fuel level therein, and means regulating the depression applied to the depression chamber from said nozzle and the depression applied to the fuel chamber from said depression chamber.

9. In a carburetor comprising a body, a fuel chamber and afmain air passage, an accelerating we'l comprising a vertically extending' bore in said body, an outlet passage leading from said bore-to said main air passage, "a nozzle in the lower portion of said bore, means for projecting a stream of fuel upwardly through said nozzle, and a passage leading from the fuel chamber into said bore at a point in the path of the projected 13()v fuel stream.

10. In a carburetor comprising a body, a fuel chamber and a main air passage, an accelerating Well comprising a vertically extending bore in said body, an outlet passage leading from said bore to said main air passage, a vertically directed nozzle in thev lower portion of said bore, a passage leading from the fuel chamber into said bore above the nozzle, there being a body of fuel normally standing in the bore a substantial distance above said nozzle, andmeans'for projecting a stream of fuel upwardly through the nozzle and into said bore to move said body of fuel into the outlet passage.

l1. In a carburetor comprising aV body, a fuel 145 chamber and a main air passage, an accelerating well comprising a vertically extending bore in said body, an outlet passage leading from said bore to said main -air passage, means for projecttowardl said outlet passage, a passage leading from the fuel chamber yinto said bore, and a verticallymovable and- :apertured plunger insaid bore below the outlet. l2. Inra carburetor comprising a body, a fuel chamber anda main airpassage, an accelerating well Vcomprising a vertically extending ,-bore, in said body, -an outlet passage leading from said bore to said mai-n air passage, a transverse pas sage leading .from the fuel chamber into said bore, a constriction in said bore above the. last mentioned passage, and means for projecting fuel upwardly through the constriction. f 13. In.- a carburetor comprising a body, a, fue chamber and a main air passage, an accelerating well comprising a vertically extending bore in said body, an outlet passage leading from said bore to said main air passage, means for pro.- jecting a stream of fuel upwardly within the bore toward said outlet passage, a transverse passage leading from the fuel chamber into said bore, a.

venturi in said bore above the last mentioned passage, fuel being discharged from said nozzle into the venturi, and a restricted passage inthe upper portion of said 'bore and communicating with the outlet passage.

14. In a carburetor comprising a body, a fuel chamber and a main air passage, an accelerating well comprising a vertically extending bore in said body, an outlet passage leading from said bore to said main air passage, means for projecting a stream of fuel upwardly within the bore toward said outlet passage, a transverse passage leading from the fuel chamber into said bore, a venturi in said bore above the last mentioned passage, fuel being discharged from said nozzle into the venturi, and a vertically movable apertured valve in said bore above the venturi.

15. In a carburetor having a body, a fuel chamber and a main air passage, an accelerating Well comprising a vertically extending bore in said body, an outlet passage leading `from said bore to the main air passage, a passage through which fuel is fed to said bore from the fuel chamber, there normally being a body of fuel standing in said bore, means at the lower portion of said bore for jetting fuel upwardly against said body of fuel to move the latter into said outlet passage, and means movable in said bore for restricting the rate of fuel flow into the outlet passage after discharge of a predetermined amount of fuel from said bore.

'16. `In a carburetor, the combination comprising, abody having a main air passage containing a throttle valve, an air valve floating on the air stream in said passage, a fuel supply reservoir, a.

dash pot mechanism connected to the lower end ofsaid air valve, saidmechanism comprising a fuel, containing chamben, andmeans for feeding fuel to saidchamber frcimwithin said fuel resera voirV lQm apoint above ,the normal fuel ,level therein.

17. In a carburetor', thecombination comprising, a body having a. main airpassage containing a, throttle valve, an Kair valvel floating on the air stream in said passage,A a, fuel .nozzle reservoir, a dash pot mechanism connected to the lower end of saidzair valve, A saidmechanism comprising a, fuell containing chamber, a, passage connecting said chamber with the fuel reservoir at a point above: the normal fuellevel therein, and fuel inlet means for feeding fuel to said reservoir and said passage.

18...-In a carburetor, the combination comprising, a body having a main air passage containing a throttle valve, a second valve in said passage and adapted to regulate the air flow therethrough, a manually operable member, a second relatively movable member connected thereto for limited relative motion and adapted to engage the second mentioned valveto hold the latterin closed position, and yielding means acting between the two members to hold the second mentioned member in engagement 4with the valve after valve releasing movement of the rstmentioned member.

19. A carburetor comprising a body, a fuel chambr and a main air passage having a constriction therein,l a throttle in said passage, a depression chamber in fuel communication with the fuel chamber, a depression communication between the air passage constriction and the depression chamber, a. fuel nozzle discharging into the main air passage, a passage connecting the depression chamber with the fuel nozzle, and a valve in said last mentioned passage controlling the effective size of the passage in operative relation to throttle position.

20. A carburetor comprising a body, a fuel chamber and a main air passage having a constriction therein, a throttle in said passage, a depression chamber in fuel communication with the fuel chamber, a depression communication between the air passage constriction and the depression chamber, a fuel nozzle discharging into the main air passage, a passage connecting the depression chamber with the fuel nozzle, and a valve in said last mentioned passage controlling the effective size of the passage in operative relation to throttle position, and a passage adapted to admit air to the depression chamber and con- 

